I have the pleasure to own a brand new unlocked Lumia 950XL...
I have recently joined EE (UK operator)... They support Wifi Calling which would be very handy since I don't have good signal indoors in my office...Reading through the EE community forum. There seems to be something going on with their Wifi Calling (disappearing settings!)...

My story (in short):
- I open my brand new 950XL, install OTA 10586.29 etc
- Connect to my local wifi,
- Then go to Settings -> Networks -> Mobile & Sim - > Sim setting and turn Wifi calling on ...
- Chat with EE to enabled WiFi calling on my account and receive the acknowledgment EE SMS...
The following day, I lose the mobile signal and can see a small phone icon on the wifi icon, indicating that I am now on Wifi Calling (since not mobile signal)... brilliant !

I chatted with EE customer support and he told me that only EE branded phone, with EE firmware, can use the Wifi Calling...
My device is not supported. Then I told him that I had WiFi Calling and it has been removed... he replied that this was impossible since only EE branded phone have the required EE firmware on-board to enable WiFi Calling... I told him that I set it up... it is nearly as if he didn't told me I was dreaming!!! until... I send him the screenshot I took before the Sim update... !

Horrified... he then he told me that I my warranty will be void has I have flashed my phone ??? what ??? I flashed my phone ???
I am certainly not capable of flashing my phone (and I have not reason to do so), and even less capable of getting a EE Windows 10 Mobile specific ROM from the dark web !!!!

I try to explain that it is more likely that the code is already on-board the 950XL from factory and simply disabled by the network when the phone first connect to the network (via SIM parameters)... That should have happened to me , the only thing was that the network didn't removed it fast enough for me not to use it for 1 day!... Also, there will be less and less Operator specific OS upgrade, avoiding the long waiting for Operator specifics OS update for locked devices to be tested and released by the operator! (iPhone, iOS operator specific update?).

He confirmed that I should not have had access to this feature in the first place and he doesn't understand why nor how I did (unless I flashed my device with EE ROM, which of course I didn't !).
He went back on; If I want Wifi calling, only devices purchased directly from EE will work !!! this is company policy... take it or leave it (us) ... etc the chat session was going nowhere...

Digging a bit deeper, this "policy" seems NOT to apply to iPhone, only Android and Microsoft. It seems that if you have an iphone5s and above, you can enjoy Wifi Calling (so long it is enabled on your account!)...
Why?

Then I found out in the EE community Forum that another user had the exact same issue:
EE wifi calling: you see it -> Sim parameters update -> now you don't !!!
THE difference is that he says he has bought his Lumia 950XL directly from EE as a business customer !!!
Despite having seen and connected to WiFi Calling for a day, like I did, he has been told that the 950XL doesn't support WiFi Calling ???
As a phone directly purchased from EE, surely his phone has the famous EE firmware on-board !
Furthermore, EE site does list the Lumia 950 as enabled for EE WiFi calling (and the 950XL wouldn't be capable of that ???)
The "EE company policy" of branded devices only is no longer valid !!!

What is the motivation behind removing the WiFi Calling feature from supported device??? No answers from EE

Is this purely to lock in users into buying their EE locked phone only ?
(I am already locked anyways since I am on a 24 mths contract!!!)
What's the point?

Do they try to cover up the fact that they haven't tested the 950XL yet and therefore disable it by default (being a EE or non EE phone)?

So despite the fact you are PAYING them for network access, they are saying you can go without because your device isn't branded. I've never heard such crap! Seen the screen shots so how the hell can they say not possible??

IMHO, they are pulling a fast one or they genuinely aren't aware of the devices capability. If they have turned it off it is almost comparable to them saying you can't text anyone!! I would write to them. Arguing over the phone means that they will try and blag their way out of an argument, and you have no record. Maybe inform them that you are being discriminated against, despite paying them each month, and you feel that you deserve the same treatment as anyone else. Does their T's & C's say unlocked devices are prohibited from accessing this service?

If they are 'forcing' people to buy their devices only, they are treading on very thin ice as this could be deemed as a 'restrictive' practice / unfair practice, and we all know how the EU rules frown upon such behaviour. I guess they haven't got a clue about the 950 / 950xl!!

Anyways, write to them asking why they have blocked you, or is it indeed not available on the device. The warranty aspect is complete bull! It was an official OTA from Microsoft. Do they cease warranty when they send an update out?? If not then you are, somewhat, being discriminated against again!

I gave up with EE. In my house they are known as Excuses Everytime. An absolute pile of ****. Always end up speaking to someone in the back of beyond who has an Anglican name to soften you up.

Indeed, I only do chat session with EE customer support and email the script to myself at the end... in writing...
Anyway, I have been told many stories, none of them valid!

The EE device only policy is not valid as there is another EE customer in the exact same situation, with the exact same experience of the WiFi callng settings being removed by the "sim update"... THE difference is that he got his 950XL directly from EE, this is therefore supposed to be a EE device !!
He simply has been told, by a Level 2 tech support, that the 950 is supported for EE WiFi calling, but not the 950XL !!! (you can guess what I think of that excuse !)

My guess is indeed that they don't have a clue and haven't tested the 950XL yet, so disable the feature by default !!!

in the meantime I will continue my lovely (pointless!) chats sessions with EE until they escalate...
Hopefully more people will complain about this as well (the more people "crying" the more likely they may listen!)...

Indeed, I only do chat session with EE customer support and email the script to myself at the end... in writing...
Anyway, I have been told many stories, none of them valid!

The EE device only policy is not valid as there is another EE customer in the exact same situation, with the exact same experience of the WiFi callng settings being removed by the "sim update"... THE difference is that he got his 950XL directly from EE, this is therefore supposed to be a EE device !!
He simply has been told, by a Level 2 tech support, that the 950 is supported for EE WiFi calling, but not the 950XL !!! (you can guess what I think of that excuse !)

My guess is indeed that they don't have a clue and haven't tested the 950XL yet, so disable the feature by default !!!

in the meantime I will continue my lovely (pointless!) chats sessions with EE until they escalate...
Hopefully more people will complain about this as well (the more people "crying" the more likely they may listen!)...

Time will tell!

Tony.

Enjoy the bull mate! You should have enough soon to keep a vegetable patch going for a while!! Lol!

I too, love a web chat, although sarcasm is quite difficult to put into words they understand!

Same for me
Bought a 950 from carphone warehouse (420, not bad!)
EE Wifi calling worked straight out of the box, received my sms confirmation message, etc etc etc, then it did a settings update and bam, no wifi calling.

who knows.

Although what i would say, is that before the settings update the phone was laggy and slow and things like the store and outlook would randomly crash, so actually i prefer the phone now its had the update!

Update:
My 950XL is now connected to EE Wifi calling since Friday night :-)
After 2 days of "battle" on EE Community forums, I removed my SIM, restart the phone with no SIM, then off, put the SIM back in, restarted and a minutes later I received a Sim parameter update which put the wifi calling back in the menu.
I switch it on and can now use WiFi... as expected!
For the past 2 days I have made and received call/txt over Wifi where I don't have signal... now I can use EE for the main reason I joined them...
hopefully they won't remove it again!!!